IR 05000266/2007008
ML072350175 | |
Person / Time | |
---|---|
Site: | Point Beach |
Issue date: | 08/21/2007 |
From: | Pederson C Division Reactor Projects III |
To: | Koehl D Nuclear Management Co |
References | |
IR-07-008 | |
Download: ML072350175 (57) | |
Text
ust 21, 2007
SUBJECT:
POINT BEACH NUCLEAR PLANT NRC SPECIAL INSPECTION REPORT 05000266/2007008 AND 05000301/2007008
Dear Mr. Koehl:
On June 28, 2007, the NRC completed a Special Inspection at your Point Beach Nuclear Plant to evaluate the facts and circumstances surrounding the turbine outboard bearing high temperatures associated with the Unit 1 Turbine-Driven Auxiliary Feedwater Pump (1P-29),
and the subsequent Technical Specification required shutdown on June 14, 2007. The enclosed report documents the inspection findings, which were discussed on July 12, 2007, with you and members of your staff.
The inspection examined activities conducted under your license as they relate to safety and compliance with the Commission's rules and regulations and with the conditions of your license.
The inspectors reviewed selected procedures and records, observed activities, and interviewed plant personnel.
Based on the risk and deterministic criteria specified in Management Directive 8.3, "NRC Incident Investigation Program," and Inspection Procedure 71153, "Event Followup," and due to the equipment performance problems which occurred, a Special Inspection was initiated in accordance with Inspection Procedure 93812, "Special Inspection." The Special Inspection evaluated the facts and circumstances surrounding the event, as well as the actions taken by your staff in response to the unexpected equipment condition. The inspection focus areas are detailed in the Special Inspection Charter (Attachment 4). Based on the results of this special inspection, six inspector-identified and self-revealed findings of very low safety significance (Green) were identified. Five of those findings were determined to involve violations of NRC requirements. However, because of the very low safety significance and because they are entered into your corrective action program, the NRC is treating these findings as non-cited violations (NCVs) consistent with Section VI.A.1 of the NRC Enforcement Policy.
At the conclusion of the inspection, several questions remained regarding the past operability, availability and reliability of the Unit 1 Turbine-Driven Auxiliary Feedwater Pump 1P-29 following the maintenance performed in the Spring 2007 Refueling Outage. The outcome of these questions will directly affect the significance characterization of the performance deficiency associated with post-maintenance testing and any further enforcement action taken by the NRC. Therefore, an Unresolved Item was opened to monitor your resolution of the operability, availability and reliability questions pertaining to the turbine-driven auxiliary feedwater pump following the Spring 2007 Refueling Outage. There are no current safety concerns based on the actions you and your staff have taken, which are briefly described below.
These immediate remedial corrective actions primarily included, but were not limited to:
troubleshooting, maintenance, and repair of the Unit 1 Turbine-Driven Auxiliary Feedwater Pump 1P-29 with vendor representatives; successful, adequate post-maintenance testing of the Unit 1 Turbine-Driven Auxiliary Feedwater Pump 1P-29; and extent of condition evaluations associated with the Unit 2 Turbine-Driven Auxiliary Feedwater Pump 2P-29. At the conclusion of the inspection, your staff continued working to complete the root cause evaluations for the issues identified during this event and indicated that several other long term actions would be implemented upon completion of the root cause evaluations.
The inspection team concluded, as did your staff, that the performance deficiencies identified reflect a declining trend in the area of human performance at the Point Beach Nuclear Plant.
We understand that you and your staff have developed immediate corrective actions to address this adverse trend, and we will continue to monitor those actions as part of our routine inspections.
If you contest any finding or NCV in this report, you should provide a response within 30 days of the date of this inspection report, with the basis for your denial, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001, with copies to the Regional Administrator, U.S. Nuclear Regulatory Commission - Region III, 2443 Warrenville Road, Suite 210, Lisle, IL 60532-4352; the Director, Office of Enforcement, U.S.
Nuclear Regulatory Commission, Washington, DC 20555-0001; and the Resident Inspector at the Point Beach Nuclear Plant. In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter, its enclosure, and your response (if any) will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records System (PARS)
component of NRC's document system (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).
Sincerely,
/RA/
Cynthia D. Pederson, Director Division of Reactor Projects Docket Nos. 50-266; 50-301 License Nos. DPR-24; DPR-27 Enclosure: Inspection Report 05000266/2007008; 05000301/2007008 w/Attachments: 1. Supplemental Information 2. Timeline of Events Unit 1 3. Timeline of Events Unit 2 4. Special Inspection Charter cc w/encl: F. Kuester, President and Chief Executive Officer, We Generation D. Cooper, Senior Vice President and Chief Nuclear Officer J. McCarthy, Site Director of Operations D. Weaver, Nuclear Asset Manager Plant Manager Regulatory Affairs Manager Training Manager Site Assessment Manager Site Engineering Director Emergency Planning Manager J. Rogoff, Vice President, Counsel & Secretary K. Duveneck, Town Chairman Town of Two Creeks Chairperson Public Service Commission of Wisconsin J. Kitsembel, Electric Division Public Service Commission of Wisconsin State Liaison Officer
SUMMARY OF FINDINGS
IR 05000266/2007008 and 05000301/2007008; 06/18/2007 - 06/28/2007; Point Beach Nuclear
Plant, Units 1 and 2; Special Inspection to Review Circumstances Surrounding the High Outboard Bearing Temperature Indications of the Unit 1 Turbine-Driven Auxiliary Feedwater Pump 1P-29.
This report covers a 10-day period of Special Inspection by NRC resident inspectors. The inspection identified six Green findings and one Unresolved Item. The significance of most findings is indicated by their color (Green, White, Yellow, Red) using Inspection Manual Chapter (IMC) 0609, "Significance Determination Process" (SDP). Findings for which the SDP does not apply may be "Green" or be assigned a severity level after NRC management review. The NRC's program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, "Reactor Oversight Process," Revision 3, dated July 2000.
A. Inspector-Identified and Self-Revealed Findings
Cornerstone: Mitigating Systems
- Green: The inspectors identified a finding involving a non-cited violation (NCV)of 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Action, having very low safety significance (Green) for the licensees failure to identify and implement prompt corrective actions for the conditions which caused outboard bearing high temperature alarms during the Unit 1 Turbine-Driven Auxiliary Feedwater (TDAFW) pump post-maintenance test (PMT) performed on May 1, 2007; the Unit 1 TDAFW pump PMT performed on May 6, 2007; and the Unit 2 TDAFW pump PMT performed on November 17, 2006. The licensee performed troubleshooting and repair of the Unit 1 TDAFW pump and confirmed operability of the Unit 2 TDAFW pump with needed compensatory actions. The licensee entered the issue into their corrective action program and took immediate corrective actions. At the end of the inspection period, the licensee continued to evaluate the causes and corrective actions to address this finding.
The finding was more than minor because it could reasonably be viewed as a precursor to a significant event. Specifically, the failure to identify and investigate the cause of the high bearing temperature alarms could potentially result in failure of the TDAFW pumps. Additionally, the finding is associated with the equipment performance attribute of the Mitigating Systems Cornerstone and affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Failure to identify and promptly correct the conditions which caused the high bearing temperature alarms was a condition adverse to quality and was a corrective action program issue that was determined to be a licensee performance deficiency of very low safety significance (Green). The primary cause of this finding was related to a cross-cutting aspect in the area of problem identification and resolution for the failure to implement a corrective action program with a low threshold for identifying issues completely, accurately and in a timely manner commensurate with their safety significance (P.1(a)).
(4OA3.2.b.1)
- Green: The inspectors identified a finding of very low safety significance (Green) and a non-cited violation of 10 CFR Part 50, Appendix B, Criterion V,
Instructions, Procedures, and Drawings, for the failure to adequately assess operability of the Unit 1 TDAFW pump in accordance with plant procedures.
The inspectors identified that the licensee failed to implement procedural requirements regarding the immediate assessment of operability on June 9, 2007, for the Unit 1 TDAFW pump turbine outboard bearing high temperatures. The licensee took corrective actions, which included re-performing testing to evaluate bearing stabilization temperatures and briefing of the operations crews on this issue. The licensee entered the issue into their corrective action program and took immediate corrective actions. At the end of the inspection period, the licensee continued to evaluate the causes and corrective actions to address this finding.
The finding was more than minor because, if left uncorrected, the failure to properly assess operability would result in the TDAFW pump being degraded, and possibly inoperable for more than the allowed outage time in accordance with Technical Specifications with no action being taken. The finding is of very low safety significance since the inadequate operability determination did not result in exceeding the allowed outage time of Technical Specifications before action was taken. The primary cause of this finding was related to a cross-cutting aspect in the area of human performance because the licensee failed to demonstrate that nuclear safety was an overriding priority. Specifically, the licensee failed to make safety-significant or risk-significant decisions using a systematic process for operability determinations, especially when faced with uncertain or unexpected plant conditions, to ensure safety was maintained (H.1(a)). (4OA3.2.b.2)
- Green: The inspectors identified a finding of very low safety significance and a non-cited violation of 10 CFR Part 50, Appendix B, Criterion V, Instructions,
Procedures, and Drawings, for the failure to ensure that procedures associated with the maintenance of the TDAFW turbines were appropriate to the circumstances. Specifically, the licensees maintenance overhaul procedure did not address the following significant issues: 1) specify acceptance criteria and as-left requirements for thrust bearing axial clearance; 2) specify instructions to ensure the proper setting and critical dimensions for the proper pump to turbine coupling stretch; 3) establish the correct turbine to wheel nozzle lap setting; and 4) specify proper placement of insulation on the turbine. The licensee entered the issue into their corrective action program and took immediate corrective actions. At the end of the inspection period, the licensee continued to evaluate the causes and corrective actions to address this finding.
The finding was more than minor because, if left uncorrected, the issue would have become a more significant safety concern. In addition, it affected the Mitigating Systems attributes of equipment performance availability and reliability, and maintenance procedure quality, as well as the Mitigating Systems cornerstone objective of ensuring the reliability of systems. The inspectors determined this programmatic finding was not a design qualification deficiency resulting in a loss of function per Generic Letter 91-18, did not represent an actual loss of safety function of a system or train of equipment, and was not potentially risk-significant due to a seismic, fire, flooding, or severe weather initiating event. Therefore, the finding was considered to be of very low safety significance (Green). The primary cause of this finding was related to a cross-cutting aspect in the area of human performance because the licensee failed to ensure that procedures were adequate and accurate to assure nuclear safety (H.2(c)). (4OA3.3.b.1)
- Green: The inspectors identified a finding of very low significance (Green)with no associated violation for the failure to provide appropriate training for maintenance personnel performing overhauls on the TDAFW pump turbines.
Specifically, while maintenance personnel received training on some of the individual components associated with a turbine, the mechanic-electrician (mechanical) training program did not require specialty task training for turbine overhauls. In addition, this was contrary to standard industry guidelines for training and qualification of maintenance personnel. The licensee entered the issue into their corrective action program and took immediate corrective actions.
At the end of the inspection period, the licensee continued to evaluate the causes and corrective actions to address this finding.
The finding was more than minor because, if left uncorrected, the issue would have become a more significant safety concern. In addition, it affected the Mitigating Systems attributes of equipment performance availability and reliability, and to pre-event human error, as well as the Mitigating Systems cornerstone objective of ensuring the reliability of systems. The inspectors determined this programmatic finding was not a design qualification deficiency resulting in a loss of function per Generic Letter 91-18, did not represent an actual loss of safety function of a system or train of equipment, and was not potentially risk-significant due to a seismic, fire, flooding, or severe weather initiating event. Therefore, the finding was considered to be of very low safety significance (Green). The primary cause of this finding was related to a cross-cutting aspect in the area of human performance because the licensee failed to assure that training of personnel was adequate to assure nuclear safety (H.2(b)).
(4OA3.3.b.2)
- Green: The inspectors identified a finding of very low safety significance (Green) and a non-cited violation of 10 CFR Part 50, Appendix B, Criterion V,
Instructions, Procedures, and Drawings, for the failure to adequately implement an oil analysis program for the TDAFW pump. The inspectors identified that the licensee failed to implement sampling guidelines using industry standards or provide an adequate justification for not performing the samples at reasonable intervals. The licensee entered the issue into their corrective action program and took immediate corrective actions. At the end of the inspection period, the licensee continued to evaluate the causes and corrective actions to address this finding.
The finding was more than minor because, if left uncorrected, the failure to have an adequate procedure for lubrication would result in the TDAFW pump being degraded without the knowledge of the licensee. The inspectors determined the finding did not result in an actual loss of safety function of a system or train of equipment; therefore, the finding was considered to be of very low safety significance (Green). The primary cause of this finding was related to a cross-cutting aspect in the area of human performance because the licensee did not ensure that procedures were adequate and accurate to assure nuclear safety (H.2(c)). (4OA3.5.b.1)
- Green: The inspectors identified a finding of very low safety significance (Green) and a non-cited violation of 10 CFR Part 50, Appendix B, Criterion V,
Instructions, Procedures, and Drawings, for the failure to adequately quarantine a component for subsequent causal analysis. The inspectors identified that the licensee failed to implement procedural controls to quarantine degraded components during troubleshooting and maintenance activities which resulted in the loss of evidence for causal analysis. The licensee entered the issue into their corrective action program, implemented interim quarantine controls, and issued a new Procedure, NP 1.1.17 Quarantine of Areas, Equipment, and Records.
The finding was more than minor because, if left uncorrected, the failure to properly quarantine items would become a more significant safety concern, since the failure to do so could impede the identification of causes for conditions adverse to quality and prevent the implementation of appropriate corrective actions. The inspectors determined the finding was not a design qualification deficiency resulting in a loss of function per Generic Letter 91-18, did not represent an actual loss of safety function of a system or train of equipment, and was not potentially risk-significant due to a seismic, fire, flooding, or severe weather initiating event. Therefore, the finding was considered to be of very low safety significance (Green). The primary cause of this finding was related to a cross-cutting aspect in the area of human performance because the licensee did not ensure that procedures were adequate and accurate to assure nuclear safety (H.2(c)). (4OA3.7.b.1)
Licensee-Identified Violations
No findings of significance were identified.
REPORT DETAILS
Summary of Plant Event On June 9, 2007, the Unit 1 Turbine-Driven Auxiliary Feedwater (TDAFW) Pump 1P-29 was run in accordance with Quarterly Inservice Test (IST) Procedure IT-8A. During this test, the TDAFW pump turbine outboard bearing reached a temperature of 233 degrees Fahrenheit (EF), which was 8EF over the bearing high alarm setpoint of 225EF (temperatures over 250EF required the pump to be shut down). A condition report was written indicating the temperature was increasing when the pump was secured from the IST; however, no immediate actions were taken to address the anomalous bearing temperature indication, which had not stabilized at the time the pump was secured. On June 11, licensee personnel reviewed the data from the June 9 IST and raised the concern that the pump did not appear to reach an equilibrium temperature, as evidenced by the continuing rate of increase. Based on these questions, the licensee re-performed IST IT-8A on June 12. During the test, the turbine outboard bearing temperature reached 249.5EF and the operators aborted the test, shut down the TDAFW pump, and declared the pump inoperable. As a result of an initial investigation, the licensee determined that the turbine outboard bearing was contacting the turbine shaft and oil analyses indicated the oil was subjected to thermal stress and contained moderate wear debris.
Over the next 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, the licensee attempted to identify the cause and repair the TDAFW pump. The licensee identified turbine bearing upper housing alignment issues, a potential radiative heat issue from the turbine casing insulation towards the outboard bearing, and potential turbine bearing clearance issues. However, the licensee was not able to identify the cause and repair the Unit 1 TDAFW pump within the allowed outage time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> in Technical Specification (TS) 3.7.5 and began a Unit 1 shutdown at approximately 6:30 p.m.
on June 14, 2007, due to the inoperable TDAFW Pump 1P-29.
The TDAFW pump recently had a 10-year overhaul performed in April 2007, during the Unit 1 Refueling Outage. During post-maintenance testing (PMT) in the refueling outage, the licensee identified issues with the TDAFW pump turbine outboard bearing losing excessive oil, due to an inappropriately dimensioned bearing installed as part of the overhaul. The licensee corrected that particular issue prior to the startup from the refueling outage; however, the post-maintenance testing performed was not adequate in that the TDAFW pump was not run long enough to allow the bearing temperatures to stabilize, as discussed in Section 4OA3.6.b.1 of this report. Therefore, this degraded condition existed since Unit 1 entered Mode 3 on May 3, 2007.
Based on the probabilistic risk and deterministic criteria specified in Management Directive 8.3, "NRC Incident Investigation Program," and Inspection Procedure 71153, "Event Followup," and due to the equipment performance problems which occurred, a Special Inspection was initiated in accordance with Inspection Procedure 93812, "Special Inspection."
The inspection focus areas included the following charter items:
- Establish the sequence of events related to the maintenance and testing of the Unit 1 TDAFW pump, including a historical timeline;
- Monitor and assess the licensees response to the indications of increasing turbine outboard bearing temperatures, including the operability determination, maintenance, and testing;
- Monitor and assess the licensees determination of the causes for the anomalous conditions associated with the Unit 1 TDAFW pump, to the extent practicable;
- Monitor and assess the corrective actions associated with the restoration of the Unit 1 TDAFW pump;
- Assess the licensees extent of condition evaluation associated with the Unit 1 TDAFW pump;
- Evaluate the licensees post-maintenance and routine testing of the TDAFW pump;
- Assess the licensees program and procedures for quarantining and equipment failure analysis of individual failed systems and components; and
- Assess the impact and safety significance of the increased turbine outboard bearing temperatures on the Unit 1 TDAFW pump.
The last charter item listed above will continue to be assessed via Unresolved Item (URI)
URI 05000266/2007008-06, documented in Section 4OA3.6.b.1 of this report for the post-maintenance testing performance deficiencies.
OTHER ACTIVITIES (OA)
4OA3 Special Inspection
.1 Establish the Sequence of Events Related to the Maintenance and Testing of the
Turbine-Driven Auxiliary Feedwater Pump
a. Inspection Scope
The inspectors reviewed control room logs, plant parameter recordings, historical inservice tests, corrective action documents, maintenance work order and work request history, and engineering design changes and conducted interviews to determine the relevant sequence of events associated with the maintenance and testing of the TDAFW pumps. The inspectors also reviewed work request history and corrective action program documents to evaluate the licensee's response to previous indications of high bearing temperatures.
b. Findings and Observations
Sequence of Events Timeline A detailed timeline of the relevant sequence of events related to the Unit 1 and Unit 2 TDAFW pumps is included in Attachments 2 and 3 of this Report, respectively. Findings associated with the performance deficiencies identified in the sequence of events are addressed in the remaining sections of this report.
The timeline of events demonstrated that both the Unit 1 and Unit 2 TDAFW pump turbine outboard bearings have historically exhibited high temperatures, in excess of 200EF. However, the Unit 1 TDAFW Pump 1P-29 timeline highlighted that since the Spring 2007 overhaul, the outboard bearing temperature was uncharacteristically high, leading to the conclusion that the maintenance overhaul introduced new conditions which resulted in very high temperatures observed on June 9 and 12, 2007.
.2 Monitor and Assess the Licensees Response to the Indications of Increasing Turbine
Outboard Bearing Temperatures, Including the Operability Determination, Maintenance, and Testing
a. Inspection Scope
The inspectors evaluated the licensees identification and initial response to this event.
This evaluation included the following aspects: a review of the licensee's identification of the degraded condition on June 9, 2007, and subsequent response; a review of the licensees assessment of previous high temperature indications; a review of the licensees actions during the refueling outage with respect to maintenance and testing of the TDAFW pump; the licensees response following the June 12, 2007, TDAFW pump run; and the licensees organizational response following the TS required shutdown on June 14, 2007. The inspectors attended plant meetings, interviewed plant personnel and reviewed the plant's TSs, operator logs, maintenance procedures, work orders and corrective action program documents.
b. Findings and Observations
b.1 Failure to Identify and Correct Previous Indications of the High Outboard Bearing Temperatures
Introduction:
The inspectors identified a finding involving a non-cited violation (NCV)of 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Action, having very low safety significance (Green) for the licensees failure to identify and implement prompt corrective actions for the conditions which caused outboard bearing high temperature alarms during the Unit 1 Turbine-Driven Auxiliary Feedwater (TDAFW) pump post-maintenance test (PMT) performed on May 1, 2007; the Unit 1 TDAFW pump PMT performed on May 6, 2007; and the Unit 2 TDAFW pump PMT performed on November 17, 2006. These PMTs were performed following the 10-year overhaul for these pump turbines.
Description:
On June 12, 2007, the licensee performed a special test for the Unit 1 TDAFW pump, as a result of exceeding the alarm setpoint (225EF) during a June 9, 2007, IST of the pump, to determine whether the turbine outboard bearing temperature would stabilize below the pump trip setpoint of 250EF. The temperature of the outboard bearing reached 249.5EF during this test, and the test was stopped. The Unit 1 TDAFW pump was declared inoperable and the licensee entered the 72-hour action statement per Technical Specification Action Condition (TSAC) 3.7.5.B. Attempts to repair the Unit 1 TDAFW pump turbine within the 72-hour action statement were unsuccessful, and the plant was subsequently shutdown on June 15, 2007, as required by TSAC 3.7.5.D.
The June 12, 2007 test of the Unit 1 TDAFW pump was performed to address a condition report written following the performance of the quarterly IST test on June 9, 2007. During the June 9 test, the outboard bearing temperature reached 233EF and was still rising when the pump was secured. Two other recent instances of the Unit 1 TDAFW pump turbine outboard bearing temperature exceeding the alarm setpoint occurred on May 1, 2007 (247EF), during an uncoupled run of the turbine and May 6, 2007 (238EF), during the Procedure IT-8A IST of the Unit 1 TDAFW pump, both following the 10-year overhaul. However, no condition reports were written for the unexpected high temperature alarms which were received during the tests. The inspectors also identified that a condition report was not written for a previous occurrence of the Unit 2 TDAFW pump unexpectedly exceeding its outboard bearing alarm setpoint during a PMT conducted on November 17, 2006, after a 10-year overhaul performed earlier in November.
The licensees troubleshooting and maintenance of the Unit 1 TDAFW pump turbine revealed several discrepancies introduced during the 10-year overhaul, which in the aggregate led to the high outboard bearing temperatures as discussed in Section 4OA3.3.b.1 of this report. With respect to the Unit 2 TDAFW pump turbine, IST Procedure IT-9A was performed on June 21, 2007, and identified that the Unit 2 TDAFW pump turbine outboard bearing temperature stabilized at 222EF, while running at full flow conditions. The licensee, in consultation with the turbine vendor, concluded that this as left turbine bearing temperature, although high, was acceptable for the TDAFW pump to perform its safety function. However, the licensee determined that the Unit 2 TDAFW pump was operable but degraded with compensatory measures to change bearing oil more frequently, due to water intrusion identified in an oil sample first taken on June 23, 2007, as discussed in Section 4OA3.5.b.1 of this report.
Analysis:
The inspectors determined that the licensees failure to promptly identify and correct the cause of outboard bearing alarm conditions, a condition adverse to quality, and the subsequent failure to implement prompt corrective actions was a performance deficiency that warranted a significance evaluation in accordance with Inspection Manual Chapter (IMC) 0612, Power Reactor Inspection Reports, Appendix B, Issue Screening. The finding was more than minor because it could reasonably be viewed as a precursor to a significant event. Specifically, the failure to identify and investigate the cause of the high bearing temperature alarms could potentially result in failure of the TDAFW pump turbines. Additionally, the finding is associated with the equipment performance attribute of the Mitigating Systems Cornerstone and affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences.
Using IMC 0609, Appendix A, Determining the Significance of Reactor Inspection Findings for At-Power Situations, Attachment 1, SDP Phase 1 Screening Worksheet for the Mitigating Systems Cornerstone, the inspectors determined this programmatic finding was not a design qualification deficiency resulting in a loss of function per Generic Letter 91-18, did not represent an actual loss of safety function of a system or train of equipment, and was not potentially risk-significant due to a seismic, fire, flooding, or severe weather initiating events. Therefore, the finding was considered to be of very low safety significance (Green). The risk assessment for the potential loss of safety function is attributed to the performance deficiencies associated with inadequate post-maintenance testing discussed in Section 4OA3.6.b.1 as Unresolved Item (URI)5000266/2007008-06. The primary cause of this finding was related to a cross-cutting aspect in the area of problem identification and resolution for the failure to implement a corrective action program with a low threshold for identifying issues completely, accurately and in a timely manner commensurate with their safety significance (P.1(a)).
Enforcement:
10 CFR Part 50, Appendix B, Criterion XVI, Corrective Action, requires, in part, that measures be established to assure that conditions adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective material, and equipment and nonconformances are promptly identified and corrected. Contrary to the above, a condition adverse to quality associated with the Units 1 and 2 TDAFW pump turbine high bearing temperatures being in excess of the alarm setpoint on November 17, 2006, May, 1, 2007, and May 6, 2007, was not identified in the corrective action program and therefore no prompt corrective actions were taken to address the degraded conditions for the Units 1 and 2 TDAFW pump turbines. Because of the very low safety significance of the programmatic aspect of this corrective action finding and because the finding was entered into the licensees corrective action program as CAP01096340, this violation is being treated as an NCV consistent with Section VI.A.1 of the NRC Enforcement Policy (NCV 05000266/2007008-01; 05000301/2007008-01).
The licensee took immediate corrective actions to address the issue, and at the end of the inspection period the licensee continued to evaluate the causes associated with this finding.
b.2 Failure to Appropriately Assess the Operability of the Unit 1 Turbine-Driven Auxiliary Feedwater Pump 1P-29 on June 9, 2007
Introduction:
The inspectors identified a finding of very low safety significance (Green)and a non-cited violation of 10 CFR Part 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, for the failure to adequately assess operability in accordance with plant procedures. The inspectors identified that the licensee failed to implement procedural requirements regarding the immediate assessment of operability on June 9, 2007, for the TDAFW pump high turbine outboard bearing temperatures.
Description:
On June 9, 2007, the licensee performed the Unit 1 TDAFW pump quarterly IST Procedure IT-08A. A high temperature alarm was received at 225EF on the turbine outboard bearing. Although the IST test was completed, the turbine outboard bearing temperature was still rising at 233EF. A condition report was written to document the high outboard bearing temperature alarm. Attachment E of Procedure IT-8A allowed pump operation up to 250EF, but required an engineering evaluation if the bearing temperature was in the Alert range, defined as 225EF to 250EF. The inspectors noted that the attachment did not have temperature stabilization criteria, and that the bearing temperatures had not stabilized.
The inspectors reviewed the alarm response procedure and noted that receipt of the alarm for the high turbine outboard bearing required notification of the system engineer; however, interviews conducted with the engineer concluded that the notification was not made. Operations personnel had declared the TDAFW pump operable after the test and documented in the immediate operability evaluation for the condition report that the pump passed the test, and all parameters were acceptable. No required action values were reached. The inspectors noted there was no assessment of the upward trend of turbine outboard bearing temperatures. In addition, the licensee had not assessed the condition and the TDAFW pumps capability to perform its specified safety function for the time the safety function was required, i.e. mission time. There also was no assessment of the TDAFW pumps functional capability to perform the augmented quality functions for the mission time in station blackout and potential fire scenarios. No operability recommendation (OPR) was asked for by operations department staff. On June 11, 2007, licensee personnel determined that the TDAFW pump needed to be run again to ensure that turbine bearing temperature stabilization was evaluated.
The inspectors reviewed the licensees procedure for operability, Fleet Procedure FP-OP-OL-01, Operability Determination. The procedure required a determination if a condition existed that could call into question the ability of a structure, system, or component (SSC) to perform its specified safety function. An example of such a condition was an item which met the definition of a degraded condition. A degraded condition, as defined in the fleet procedure, was a condition where there had been a loss of quality or functional capability. An example included in the definition was a noticeable change in parameters that were precursors to failure, for example temperature. The attachment guidance for immediate operability review also highlighted questions for performing operability determinations, which included the following: Could the capability of a SSC to prevent or mitigate consequences of an accident as postulated in the Updated Final Safety Analysis Report (UFSAR) be reduced? The guidance suggested that an OPR should be requested if additional engineering evaluation and justification was needed to answer those questions.
Finally, the inspectors noted that the guidelines for operability recommendations included guidance to evaluate trend data to identify a deteriorating condition and to utilize an OPR to predict the point when a SSC may become inoperable. However, based on interviews with operations personnel, the inspectors concluded that operations personnel did not utilize the procedure in assessing immediate operability for the condition report written on June 9, 2007.
The inspectors concluded the licensee had not adequately implemented the procedures for operability determinations. The licensee had not assessed the parameter of bearing temperature and rise of the temperature with respect to the specified safety functions and the time this function would be needed. Also, the licensee had not engaged engineering personnel for further evaluation on the capability of the Unit 1 TDAFW Pump 1P-29 to perform its safety function with the increase in turbine outboard bearing temperature.
Analysis:
The inspectors determined that the failure to adequately perform an operability determination was a performance deficiency that warranted a significance evaluation in accordance with IMC 0612, Power Reactor Inspection Reports, Appendix B, Issue Screening. The finding was more than minor because, if left uncorrected, the failure to properly assess operability would result in the TDAFW pump being degraded and potentially inoperable, exceeding the allowed outage time in accordance with TSs .
The inspectors also determined that the finding impacted the human performance attribute of the Mitigating Systems Cornerstone and impacted the cornerstone objective to ensure reliability of systems that respond to initiating events. Using IMC 0609, Appendix A, Determining the Significance of Reactor Inspection Findings for At-Power Situations, Attachment 1, SDP Phase 1 Screening Worksheet for IE, MS, and B Cornerstones, the inspectors determined the finding may have resulted in a late determination of an actual loss of safety function of a system or train of equipment. The risk assessment for the potential loss of safety function is attributed to the performance deficiencies associated with inadequate post-maintenance testing discussed in Section 4OA3.6.b.1 as URI 5000266/2007008-06. This finding, for the inadequate operability assessment, did not cause the loss of safety function for greater than the allowed outage time.
Therefore, the finding was considered to be of very low safety significance (Green).
The primary cause of this finding was related to a cross-cutting aspect in the area of human performance because the licensee failed to demonstrate that nuclear safety was an overriding priority. Specifically, the licensee failed to make safety-significant or risk-significant decisions using a systematic process for operability determinations, especially when faced with uncertain or unexpected plant conditions, to ensure safety is maintained (H.1(a)).
Enforcement:
10 CFR Part 50, Appendix B, Criterion V, requires, in part, that activities affecting quality be prescribed and accomplished by procedures appropriate to the circumstances. The licensee failed to implement the operability determination Procedure FP-OP-OL-01, Operability Determination. Procedure FP-OP-OL-01 required, in part, that the licensee assess the capability of a SSC to prevent or mitigate consequences of an accident as postulated in the UFSAR. Contrary to the above, the licensee failed to adequately assess the operability of the turbine outboard bearing for the Unit 1 TDAFW pump as the turbine bearing performance degraded. Because this finding was of very low safety significance and because the finding was entered into the licensees corrective action program as CAP01097757, this violation is being treated as a non-cited violation (NCV 0500266/2007008-02) consistent with Section VI.A of the NRC Enforcement Policy.
The licensee took immediate corrective actions to address the issue, and at the end of the inspection period the licensee continued to evaluate the causes associated with this finding.
.3 Monitor and Assess the Licensees Determination of the Causes for the Anomalous
Conditions Associated with the Unit 1 Turbine-Driven Auxiliary Feedwater Pump
a. Inspection Scope
The inspectors evaluated the licensee's determination of the causes for the increased bearing temperatures associated with the Unit 1 TDAFW turbine since the Spring 2007 Refueling Outage. The inspectors reviewed and assessed the licensees 10-year overhaul procedure utilized during the Unit 1 TDAFW turbine overhaul as compared to vendor manuals and available industry guidance on turbine maintenance, to ascertain the adequacy of the licensees procedures. In addition, the inspectors reviewed maintenance work packages and corrective action documents related to the 10-year overhauls performed on the Unit 1 TDAFW turbine in 2007 and 1998. The inspectors also reviewed the maintenance training program associated specifically with turbine overhauls to assess the adequacy of training received by maintenance personnel.
The inspectors interviewed engineering, operations, maintenance and onsite vendor personnel, attended licensee meetings, and reviewed relevant work package, training and corrective action program documents.
b. Findings and Observations
b.1 Inadequate Procedures Associated with the Turbine 10-year Overhaul
Introduction:
The inspectors identified a finding of very low safety significance (Green)and a non-cited violation of 10 CFR Part 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, for the failure to ensure that procedures associated with the maintenance of the turbines for the TDAFW pump were appropriate to the circumstances. Specifically, the licensees maintenance overhaul procedure did not address the following significant issues: 1) specify acceptance criteria and as-left requirements for thrust bearing axial clearance; 2) specify instructions to ensure the proper setting and critical dimensions for the proper pump to turbine coupling stretch; 3) correctly establish the turbine-to-wheel nozzle lap setting; and 4) specify proper placement of insulation on the turbine.
Discussion: As part of the Unit 1 Refueling Outage U1R30, the licensee performed a 10-year overhaul of the TDAFW Pump 1P-29 Turbine. The overhaul was not performed with the assistance of a vendor representative and included the work on the following items: the turbine shaft, governor drive gearbox, governor and governor drive coupling, pump to turbine coupling, gland seals, all bearings, and equipment realignment. The Unit 2 TDAFW Pump 2P29 Turbine had been rebuilt in the Fall 2006 Refueling Outage, with assistance from a vendor representative, and did not exhibit the same anomalous stabilized turbine outboard bearing temperature.
The inspectors reviewed the maintenance performed during the Unit 1 outage and noted that several condition reports were written due to issues encountered as part of the maintenance. During the course of the overhaul, one-half of the pump to turbine coupling was installed backwards, which was corrected during the refueling outage.
The licensee determined that the overhaul procedure instructions were not adequate, in that Procedure RMP 9044-1, Auxiliary Feedwater Pump Terry Turbine Overhaul, Revision 11, did not give adequate instructions for installation of the coupling. In addition, during uncoupled turbine testing conducted on May 1, 2007, following the overhaul, the outboard bearing housing began leaking significant amounts of bearing oil.
This also was corrected, and the licensee determined that the outboard journal bearing, which was installed during the overhaul, had the incorrect chamfer dimensions creating an interference fit with the housing, when an oil drain path gap was required. Due to the interference fit, the bearing oil, which was recirculated by slinger rings only, leaked out and over the outboard journal bearing because there was no oil drain path to the sump.
The licensee determined Procedure RMP 9044-1, did not provide adequate instructions for installation, since acceptance criteria for the as-left clearance of the outboard bearing oil drain path were not specified. As is discussed in Section 4OA3.6.b.1 of this report, the inadequate post-maintenance testing, performed following the 10-year overhaul, failed to identify additional maintenance overhaul issues which were discovered following the June 14, 2007, Unit 1 shutdown due to the high outboard bearing temperatures.
Following the June 12, 2007 TDAFW Pump 1P-29 run, in which the turbine outboard bearing temperature reached 249.5EF without stabilization, the pump was declared inoperable, and the licensee commenced complex troubleshooting. The troubleshooting which occurred from June 12 through June 14, 2007, but did not identify and correct the cause of the high outboard bearing temperature; however, the licensee did identify that the installation sequence of the turbine outboard bearing cover used during the overhaul caused the bearing to become slightly askew in the housing, due to interferences with the right angle drive for the governor and bent outboard bearing cover alignment pins.
In addition, the turbine insulation was found to direct radiant heat from the turbine housing directly across the outboard bearing thermocouple, and the right angle drive gearbox was discovered misaligned. Following correction of those items, the licensee performed a bearing stabilization run which was aborted after the outboard bearing temperature achieved 247.5EF during the evening of June 14, 2007, and the licensee commenced a TS required shutdown due to the fact that the TDAFW pump would not be returned to an operable status within the allowed outage time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
The inspectors began reviewing Procedure RMP 9044-1, Revision 11, as compared to the Electric Power Research Institute (EPRI) Technical Report (TR) 1007461, Terry Turbine Maintenance Guide, AFW Application, to identify whether the licensees procedure incorporated all relevant industry guidance into the maintenance procedure.
The inspectors determined that for a few tasks the industry guidance was implemented, but that a majority of tasks, which included critical measurements, such as instructions detailing the specification of acceptance criteria and as-left requirements for thrust bearing axial clearance, and the installation of the turbine bearing covers, were not incorporated into the licensees maintenance procedure. In addition, the inspectors determined that the licensee did not have any justification supporting why the industry guidance was not applicable or incorporated into the maintenance procedures.
Additional troubleshooting conducted by the licensee from June 14 through June 19, 2007, identified that the maintenance overhaul during the Refueling Outage introduced the following incorrect conditions: the thrust bearing axial clearance was left at 0.004",
when the actual clearance was required to be 0.010" to 0.015"; the pump to turbine coupling shim pack stretch was discovered to be set incorrectly, 0.015" was required, and the as-found gap around the hubs was found to be significantly less than the acceptance criteria at some points; and the turbine wheel lap setting was found to be 5/64" to 7/64" too far toward the pump to coupling end, which allowed the steam nozzle in the turbine to be positioned incorrectly over the edge of the outboard side of the turbine wheel. A TDAFW pump run was conducted on June 19, 2007, and the outboard bearing temperature stabilized at approximately 230.8EF.
The licensee continued to adjust the turbine insulation over the next couple of days to reduce the outboard bearing temperature further, and, on June 23, 3007, the final PMT run of the TDAFW pump had a turbine outboard bearing stabilization temperature of 226EF. The licensee, in consultation with the turbine vendor, concluded that this as-left temperature, although high, was acceptable for the TDAFW pump to perform its safety function.
Although several overhaul maintenance issues were identified during the licensees troubleshooting efforts, the inspectors concluded that the licensees failure to ensure the maintenance overhaul procedure prescribed appropriate instructions for the following attributes was the most significant contributor to the increased TDAFW Pump turbine outboard temperatures: 1) specification of an acceptance criteria and as-left requirements for thrust bearing axial clearance; 2) specification of instructions to ensure the proper setting and critical dimensions for the proper pump-to-turbine coupling stretch; 3) establishment of the correct turbine-to-wheel nozzle lap setting; and 4) specification of the proper placement of insulation on the turbine.
The inspectors noted that had the licensee more thoroughly utilized the guidance contained in the EPRI Technical Manual for Terry Turbine Maintenance for TDAFW applications, the overhaul procedure would have prescribed appropriate instructions for the maintenance overhaul deficiencies identified after June 12, 2007. In addition, the licensee identified that the incorrect wheel lap setting was a direct result of an error introduced into Procedure RMP 9044-1, Revision 11, which was approved in March 2007. Following the Unit 2 TDAFW pump turbine overhaul which took place in the Fall of 2006, the licensee significantly modified Procedure RMP 9044-1, which introduced procedure errors not present during the Unit 2 turbine overhaul.
Analysis:
The inspectors determined that the failure to ensure that procedures associated with the corrective and preventive maintenance of the turbine for the TDAFW pump were appropriate to the circumstances and included appropriate acceptance criteria was a licensee performance deficiency warranting a significance evaluation. The finding was more than minor because, if left uncorrected, the issue would have become a more significant safety concern. In addition, it affected the Mitigating Systems attributes of equipment performance availability and reliability, and maintenance procedure quality, as well as the Mitigating Systems cornerstone objective of ensuring the reliability of systems.
Using IMC 0609, Appendix A, Determining the Significance of Reactor Inspection Findings for At-Power Situations, Attachment 1, SDP Phase 1 Screening Worksheet for the mitigating systems cornerstone, the inspectors determined this programmatic finding was not a design qualification deficiency resulting in a loss of function per Generic Letter 91-18, did not represent an actual loss of safety function of a system or train of equipment, and was not potentially risk-significant due to a seismic, fire, flooding, or severe weather initiating event. Therefore, the finding was considered to be of very low safety significance (Green). The risk assessment for the potential loss of safety function is attributed to the performance deficiencies associated with inadequate post-maintenance testing discussed in Section 4OA3.6.b.1 as URI 5000266/2007008-06. The primary cause of this finding was related to a cross-cutting aspect in the area of human performance because the licensee failed to ensure that procedures were adequate and accurate to assure nuclear safety (H.2(c)).
Enforcement:
10 CFR Part 50, Appendix B, Criterion V, Instructions, Procedures and Drawings, requires, in part, that activities affecting quality be prescribed by documented instructions or procedures of a type appropriate to the circumstances and included appropriate quantitative or qualitative acceptance criteria to determine that the activities were satisfactorily accomplished. Contrary to this, the licensees maintenance overhaul procedure did not: 1) specify quantitative acceptance criteria and as-left requirements for thrust bearing axial clearance; 2) specify instructions to ensure the proper setting and critical dimensions for the proper pump to turbine coupling stretch; 3) correctly establish the turbine to wheel nozzle lap setting; and 4) incorporate additional relevant industry guidance to ensure the turbine was properly assembled. Because of the very low safety significance of this finding and because the finding was entered into the licensees corrective action program as CAP01090456, this violation is being treated as an NCV, consistent with Section VI.A.1 of the NRC Enforcement Policy (NCV 05000266/2007008-03; 05000301/2007008-03).
The licensee took immediate corrective actions to address the issue, and at the end of the inspection period the licensee continued to evaluate the causes associated with this finding.
b.2 Inadequate Maintenance Training Associated with Turbine Overhauls
Introduction:
The inspectors identified a finding of very low significance (Green) with no associated violation for the failure to provide appropriate training for maintenance personnel performing overhauls on the TDAFW pump turbines. Specifically, while maintenance personnel received training on some of the individual components associated with a turbine, the mechanic-electrician (mechanical) training program did not require specialty task training for turbine overhauls. In addition, this was contrary to standard industry guidelines for training and qualification of maintenance personnel.
Discussion: The inspectors interviewed several maintenance personnel, including maintenance management and supervision, and determined that the maintenance personnel had not received specialized training for turbine overhauls. The inspectors subsequently reviewed Training Program Description MM-TP, Point Beach Mechanic-Electrician (Mechanical) Training Program, Revision 2, and determined that the only specialized tasks these personnel were trained on included: snubber maintenance; overhaul of charging pump varidrives; overhaul of steam generator feed pumps; replacement of reactor coolant pump seals; overhaul of traveling water screens; overhaul of emergency diesel generators; advanced machining; heating, ventilation, and air conditioning maintenance; and reactor refueling maintenance. The licensee initially stated that the philosophy, with respect to this particular maintenance activity, was that it was covered by the subtasks the mechanics were trained on, such as the installation of sliding and contact bearings, disassembly and assembly of drive couplings and performing alignments with a laser alignment device.
The inspectors inquired whether or not a task analysis was completed for the activity of performing the 10-year overhaul of the turbine, and the licensee concluded that a task analysis had not been performed. The inspectors referenced Procedure FP-T-SAT, Analysis Phase, Revision 5, and concluded this task was difficult to perform, was critical for safe and efficient plant operation, and therefore should have been considered for initial and continuing training. In addition, the inspectors also identified that standard industry guidance for the training and qualification of maintenance personnel discussed the need for specialized skills training for turbine overhauls and alignment. The licensee determined there was no justification for not following industry guidance, and that a previous gap analysis of the licensees maintenance training program did not consider the specialized skills training listed within the industry guidance. The inspectors concluded that the licensees training program did not adequately address the specialized task of performing turbine overhauls; therefore, maintenance personnel had not received adequate training on the performance of this task.
Finally, the inspectors noted during the maintenance activities, that maintenance staff had incorrectly blue-checked a bearing by rotating the turbine shaft in the opposite direction the turbine rotated. Engineering and other personnel present rationalized this as an acceptable practice; however, bearings were required to be checked in the direction of turbine rotation. The licensee also identified other deficient maintenance practices during the June 2007 restoration of the turbine, which may have related to training or maintenance practices, including the failure to take measurements to the correct accuracy for tolerances, and incorrect measurement of the coupling gap. In addition, the licensee also noted the incorrect use of not applicable, or N/A, when performing maintenance procedure steps which led to minor errors, implementation of procedures with unclear prescribed instructions, and some cases of an incorrect integration of work plan activities with the maintenance procedures. The inspectors concluded these practices further corroborated the assessment that maintenance personnel had not received adequate training.
Analysis:
The inspectors determined that the failure to establish appropriate training for maintenance personnel performing overhauls on the TDAFW pump turbines was a licensee performance deficiency warranting a significance evaluation. This inspector identified finding was more than minor because, if left uncorrected, the issue would have become a more significant safety concern. In addition, it affected the Mitigating Systems attributes of equipment performance availability and reliability, and to prevent human error, as well as the Mitigating Systems cornerstone objective of ensuring the reliability of systems.
Using IMC 0609, Appendix A, Determining the Significance of Reactor Inspection Findings for At-Power Situations, Attachment 1, SDP Phase 1 Screening Worksheet for the mitigating systems cornerstone, the inspectors determined this programmatic finding was not a design qualification deficiency resulting in a loss of function per Generic Letter 91-18, did not represent an actual loss of safety function of a system or train of equipment, and was not potentially risk-significant due to a seismic, fire, flooding, or severe weather initiating event. Therefore, the finding was considered to be of very low safety significance (Green). The risk assessment for the potential loss of safety function is attributed to the performance deficiencies associated with inadequate post-maintenance testing discussed in Section 4OA3.6.b.1 as URI 5000266/2007008-06. The primary cause of this finding was related to a cross-cutting aspect in the area of human performance because the licensee failed to assure that training of personnel was adequate to assure nuclear safety (H.2(b)).
Enforcement:
The failure to establish appropriate training for maintenance personnel performing overhauls on the TDAFW pump turbines was not an activity subject to 10 CFR Part 50, Appendix B, nor a procedure required by license conditions or TSs.
Therefore, while a performance deficiency existed, no violation of regulatory requirements occurred. This was considered a finding of very low safety significance (FIN 05000266/2007008-04; 05000301/2007008-04).
The licensee took immediate corrective actions to address the issue, and at the end of the inspection period the licensee continued to evaluate the causes associated with this finding.
.4 Monitor and Assess the Corrective Actions Associated with the Restoration of the Unit 1
Turbine-Driven Auxiliary Feedwater Pump
a. Inspection Scope
The inspectors evaluated the licensees troubleshooting and subsequent restoration activities to address the high outboard TDAFW pump turbine bearing temperatures.
The inspectors interviewed licensee and vendor personnel, reviewed licensee troubleshooting and work plans, verified condition reports were written for issues which were identified, observed and reviewed maintenance activities, and observed portions of the return to service and post-maintenance testing.
b. Findings and Observations
No findings of significance were identified. The potential causes for the high bearing temperatures identified at the end of the inspection are discussed in Section 4OA3.3.b.1 and observations concerning the actual maintenance are contained in Section 4OA3.3.b.2 of this report.
.5 Assess the Licensees Extent of Condition Evaluation Associated with the Unit 1
Turbine- Driven Auxiliary Feedwater Pump
a. Inspection Scope
The inspectors attended licensee meetings, interviewed plant personnel, observed maintenance and testing activities, reviewed pertinent extent of condition issues for other safety-related components, and performed system walkdowns to assess the adequacy of the licensee's corrective actions for any potential extent-of-condition issues.
The inspectors reviewed potential extent-of-condition issues, based on the facts associated with the TDAFW pumps, and subsequently focused the extent-of-condition reviews on the key areas that the inspectors identified were most vulnerable. The first area was the licensees oil sampling and analysis program used for predictive and preventive maintenance on safety-related equipment. The second area reviewed was the potential extent-of-condition associated with inadequate post-maintenance testing of safety-related equipment.
b. Findings and Observations
b.1 Inadequate Oil Analysis Program Procedures
Introduction:
The inspectors identified a finding of very low safety significance (Green)and a non-cited violation of 10 CFR Part 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, for the failure to adequately implement an oil analysis program for the TDAFW pump. The inspectors identified that the licensee failed to implement sampling guidelines using industry standards or provide an adequate justification for not performing the samples at reasonable intervals.
Description:
The inspectors noted during a review of the Unit 2 TDAFW turbine outboard bearing temperature data following the Fall 2006 10-year maintenance overhaul of the turbine, that the outboard bearing temperatures dropped over 20EF in less than one half-hour during pump testing on November 11, 2006. The inspectors inquired about the oil samples which were taken after this anomalous condition. Licensee personnel indicated that no oil samples were taken since the sampling frequency was 18 months. The inspectors were concerned about the possibility of oil contamination or future bearing degradation, because the licensee explained that the rapid decrease was likely due to the bearing wearing in following the maintenance. The inspectors continued to question the adequacy of the turbine outboard oil and the licensee sampled the oil on Unit 2 TDAFW pump outboard bearing housing prior to running the pump on June 21, 2007.
The oil sample indicated some particulate and observable water, as noted by a cloudy sample. The licensee visually estimated the concentration of water in the oil to be approximately 500 to 1,000 parts per million (ppm). The EPRI Technical Report (TR) 1007461, Terry Turbine Maintenance Guide, AFW Application, an industry standard for this TDAFW, had a limit for operability of 5,000 ppm water. The actual concentration of water in this oil sample could not be determined because the licensees analysis was not capable of determining such a high water content. In addition, the work order used to obtain the oil sample was not written in accordance with the licensees standard sampling guidelines, which caused the oil sample to be used in its entirety in the inappropriate onsite analysis. Therefore, the licensee did not have additional oil to send for offsite laboratory analysis. The inspectors continued to question the licensees onsite analysis results for prior samples, and the licensee determined that the onsite oil analysis was not capable of determining the high water content because the licensees equipment was not adequately calibrated.
The licensee subsequently performed the Unit 2 TDAFW pump IST Procedure IT-9A with a requirement to reach bearing temperature stabilization on June 21, 2007, and obtained another turbine outboard oil sample. The licensee determined the post-run water concentration was approximately 160 ppm water, and initiated Condition Report CAP1098358. The licensee subsequently performed an OPR for determining the maximum allowed water to ensure the TDAFW pump could perform its safety function.
The turbine oil requirements listed in EPRI TR 1007461 recommended oil moisture content be sampled on a monthly basis and that acidity, viscosity and particle count be verified once per quarter. The licensee performed oil analysis once every 18 months and did not perform acidity checks. The licensee had no trend documentation or reasonable justification for the performance of oil samples at such a long interval, which did not coincide with standard industry and vendor guidance. The licensees lubrication analysis program, prescribed in Predictive Maintenance Manual (PDM) 2.0 states, in part, that the frequency of sampling is determined by the factors listed in the Condition Monitoring Program Procedure NP 7.3.10. Procedure NP 7.3.10 guidance on analysis frequency stated, in part, that great emphasis should be placed on trends rather than actual values. Additionally the severity of a condition must be determined by all observed symptoms and consider prior experience with similar equipment, industry standards, regulatory requirements and vendor recommendations.
The inspectors concluded that the guidance in the condition monitoring program was not adequate to ensure that the oil samples for the TDAFW pumps were reasonably evaluated, considering industry standards and vendor recommendations.
Analysis:
The inspectors determined the failure to have an adequate performance monitoring program for lubrication oil for the TDAFW pumps was a performance deficiency that warranted a significance evaluation in accordance with IMC 0612, Power Reactor Inspection Reports, Appendix B, Issue Screening. This finding was determined to be more than minor because if left uncorrected, the failure to have an adequate procedure for lubrication would result in the TDAFW pumps being in a degraded condition without the knowledge of licensee personnel.
The inspectors also determined the finding impacted the equipment performance attribute of the Mitigating Systems Cornerstone and impacted the objective to ensure the reliability of systems that respond to initiating events. Using IMC 0609, Appendix A, Determining the Significance of Reactor Inspection Findings for At-Power Situations, 1, SDP Phase 1 Screening Worksheet for IE, MS, and B Cornerstones, the inspectors determined that the finding did not result in an actual loss of safety function of a system or train of equipment. Therefore, the finding was considered to be of very low safety significance (Green). The primary cause of this finding was related to a cross-cutting aspect in the area of human performance because the licensee did not ensure that procedures were adequate and accurate to assure nuclear safety (H.2(c)).
Enforcement:
10 CFR Part 50, Appendix B, Criterion V, requires, in part, that activities affecting quality be prescribed and accomplished by procedures appropriate to the circumstances. The licensees condition monitoring procedure, NP 7.3.10, included lubrication requirements and two of those components were the safety-related Unit 1 and Unit 2 TDAFW pumps. Contrary to the above, the licensee failed to prescribe adequate lubrication monitoring procedures to assess the performance of the turbine outboard bearing oil for the TDAFW pumps of both units. Because this finding was of very low safety significance and because the finding was entered into the licensees corrective action program as CAP01099386, this violation is being treated as a non-cited violation (NCV 0500266/2007008-05; NCV 05000301/2007008-05) consistent with Section VI.A of the NRC Enforcement Policy.
The licensee took immediate corrective actions to address the issue, and at the end of the inspection period the licensee continued to evaluate the causes associated with this finding.
b.2 Review of Other Safety-Related Equipment Post-Maintenance Testing
Introduction:
No findings of significance were identified. As a result of the post-maintenance testing performance deficiencies identified in Section 4OA3.6.b.1 of this report, the inspectors reviewed any potential extent of condition issues. The inspectors reviewed the licensees post-maintenance testing procedure and use of the procedure, and reviewed post-maintenance testing performed following major maintenance to determine if issues potentially existed with other risk significant and safety-related equipment.
Discussion: The inspectors reviewed Procedure NP 10.2.7, Post-maintenance/Return to Service Testing, and concluded that it and the associated Post-maintenance Test Matrix, PBF-9809, dated February 2004, contained adequate guidance for determining appropriate post-maintenance tests; however, the procedure did not require referencing of the test matrix if an existing procedure contained PMT requirements. As a result, the inspectors noted that there may have been an error introduced into the licensees process when bearing temperature stabilization was no longer required by the American Society of Mechanical Engineers,Section XI Code for Inservice Testing, which was changed at Point Beach in 1998.
While the inspectors agreed that the Code no longer required bearing temperature stabilization, major maintenance performed on equipment where bearing replacement has occurred does require the assurance that the bearing was installed correctly. Post-maintenance testing for bearing replacements should then include bearing temperature stabilization to ensure a new issue was not introduced which could affect the pump or turbines operability following bearing replacement. In fact, the inspectors noted that the licensees post-maintenance testing matrix called for monitoring turbine bearing temperatures as part of the PMT process when turbine bearings were replaced.
The inspectors also interviewed staff responsible for determining the appropriate PMT following maintenance, which included operations, maintenance, work planning and engineering personnel. The inspectors determined that the procedure and matrix were not consistently utilized among licensee personnel to ensure the appropriate PMT was performed; licensee personnel, in some cases, solely relied on the applicable procedure being correct and did not verify that the correct PMT was specified in procedures; and that licensee personnel may not have received training on the use of the procedure and matrix. These minor issues were captured in the licensees corrective action program and were being addressed in the causal analysis for Condition Report CAP01090456.
Finally, the inspectors reviewed major corrective and preventive maintenance performed since 2001 for a select sample of components in the Safety Injection and Emergency Diesel Generator systems, to determine whether potential operability issues existed due to inadequate post-maintenance testing. The inspectors did not identify any potential operability issues associated with these reviews.
.6 Evaluate the Licensees Post-maintenance and Routine Testing of the Turbine-Driven
Auxiliary Feedwater Pump
a. Inspection Scope
The inspectors attended licensee meetings, interviewed plant personnel, observed maintenance activities, and reviewed applicable procedures and corrective action program documents.
b. Findings and Observations
b.1 Unresolved Item (URI): Inadequate Post-Maintenance Test (PMT) Following Unit 1 TDAFW Pump Turbine Overhaul
Introduction:
The inspectors identified a URI associated with the licensees failure to conduct adequate PMT of the TDAFW pumps following a 10-year overhaul of the turbine.
Description:
The licensee completed an overhaul of the Unit 1 TDAFW turbine and the associated post-maintenance testing on May 6, 2007, declaring the TDAFW pump operable following completion of the quarterly IST Procedure IT-8A. The PMT requirements for the overhaul were listed in the maintenance overhaul procedure, RMP 9044-1. The IST procedure had no specific requirements to monitor bearing temperatures for stabilization other than to perform the IST test which recorded bearing temperature data. The procedure did have a temperature limit to place the pump in the alert range and conduct an engineering evaluation when the turbine outboard bearing exceeded 225EF; and to remove the pump from service and declare the pump inoperable when the same bearing exceeded 250EF. However, as part of the PMT for the 10-year overhaul there was no requirement in either the work order, maintenance procedure or the IST procedure to ensure bearing temperatures were stabilized.
During testing on May 1, 2007, the inspectors noted that the outboard bearing temperature reached 247EF, as indicated on the chart recorders. During the PMT on May 6, 2007, some licensee personnel noted the turbine outboard bearing rising, but indicated the temperatures was stabilizing. However, the licensee did not wait for temperature stabilization and secured the Unit 1 TDAFW. The inspectors review of chart recorders revealed that the outboard bearing temperature was at 238EF and still rising. The licensee had declared the TDAFW pump operable with no PMT assessment of the outboard bearing temperature trend and no engineering analysis or evaluation of the changes in outboard bearing temperature from prior to the overhaul.
During the Unit 1 TDAFW pump quarterly IST Procedure IT-8A performance on June 9, 2007, turbine outboard bearing temperature exceeded 225EF. The turbine outboard bearing was temperature at 233EF and still rising when the pump was secured when the test was completed. In this case, a condition report was written and a follow-up test was completed on June 12, 2007, with the goal to attain bearing temperature stabilization.
The test was stopped at around 249.5EF, prior to bearing temperature stabilization, as the machine approached the 250EF limit to secure the pump. The pump was declared inoperable and the plant was subsequently shutdown to repair the TDAFW turbine.
The licensees preliminary causal analysis indicated the turbine was improperly assembled during the overhaul in May 2007, as discussed in Section 4OA3.3.b.1 of this report. The inspectors concluded that the PMT performed following the 10-year overhaul was not adequate to detect deficiencies in the maintenance performed, and that the PMT should have detected that the bearing temperatures were rising and required evaluation prior to declaring the TDAFW operable. This is a performance deficiency that requires further assessment. This finding affected the Mitigating Systems Cornerstone objective because the TDAFW pumps safety function and augmented quality function were impacted. This finding was greater than minor, because the inadequate PMT resulted in the return to service of the TDAFW pump in a degraded condition, which impacted the Mitigating Systems Cornerstone objective of availability and reliability and the attribute of equipment performance.
The licensee is assessing the impact of bearing degradation on the availability of the Unit 1 TDAFW pump to perform the design and augmented quality functions in the plants licensing basis in the corrective action program as CAP01090456. There is no current safety concern with either units TDAFW pumps, because both have been adequately tested and bearing stabilization indicated that the pumps functionality is currently maintained for all licensing and design basis events. This issue is an Unresolved Item (URI 05000266/2007008-06) until the NRC reviews the licensees past operability assessment.
.7 Assess the Licensees Program and Procedures for Quarantine and Equipment Failure
Analysis of Individual Failed Systems and Components
a. Inspection Scope
The inspectors attended licensee meetings, interviewed plant personnel, visited work sites and reviewed troubleshooting plans, work packages, and procedures to assess the licensees quarantine process.
b. Findings and Observations
b.1 Failure to Prescribe an Appropriate Quarantine Process
Introduction:
The inspectors identified a finding of very low safety significance (Green)and a non-cited violation of 10 CFR Part 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, for the failure to adequately quarantine a component for subsequent causal analysis. The inspectors identified that the licensee failed to establish and implement procedural controls to quarantine components during maintenance and troubleshooting activities.
Description:
Following a bearing stabilization test for the Unit 1 TDAFW pump on June 12, 2007, the licensee opened the outboard bearing casing on the Unit 1 TDAFW pump to inspect the bearings. Inspection of the bearings revealed scuff marks on the journal bearing. The bearing was installed during the May 2007 10-year overhaul of the Unit 1 TDAFW pump turbine. During subsequent trouble shooting activities and with the agreement of the turbine vendor, the licensee decided to machine the bearing to improve oil flow between the bearing and the shaft, in an attempt to lower the outboard bearing operating temperature. The outboard bearing, which was in the turbine at the completion of the 10-year overhaul, was selected for machining and reinstallation by licensee personnel. Licensee personnel did not consider that machining would remove the bearing scuff and wear marks, in addition to any other indications of potential heating, for subsequent causal and past operability analysis. The licensee failed to implement appropriate quarantine controls to establish positive control over the bearing to ensure that the as-found condition was preserved.
The inspectors reviewed the licensees procedures that established equipment quarantine controls. These controls were contained in FP-PA-ARP-02, NMC Augmented Incident Evaluation Procedure. This procedure required, in part, that quarantined equipment be controlled by the Shift Manager and restricted when possible, from maintenance, operations, or tampering by either:
- (1) taping or roping off quarantined areas and posting signs for preventing access without Shift Manager authorization, or
- (2) posting personnel in the accessible areas with specific instruction on applicable methods for gaining entry into the area. The incident investigation checklist included in the procedure required: identification as to whether quarantine was necessary; designation of the system, component, or area quarantined; and the dates when the quarantine was established and lifted.
Site procedure NP 5.3.3, Incident Investigation and Post-Trip Review, required that access to quarantined areas must be approved by the Duty Shift Supervisor or his designee, with the understanding that no manipulations or physical changes could occur on the affected equipment. The procedure further required that equipment was restricted from maintenance by means similar to those specified in FP-PA-ARP-02, NMC Augmented Incident Evaluation Procedure. Finally, the procedure required that if quarantined components or equipment must be altered or repaired for the purposes of nuclear or personnel safety, that videotapes or photographs will be taken, if possible, prior to any work commencing.
The inspectors determined the licensee did not implement these incident investigation procedures for the trouble shooting and maintenance activities for the Unit 1 TDAFW pump; hence, the quarantined controls contained within these procedures were not implemented. However, the inspectors also noted that the subject procedures were generally written to address major events, and thus the licensees procedure did not adequately prescribe controls for preservation of individual components in the event of significant failures or equipment malfunctions. In fact, the inspectors had previously questioned the licensee regarding the lack of adequate quarantine controls for significant component level failures. Finally, the inspectors noted that following the June 12, 2007, test that confirmed the high turbine outboard bearing temperatures, the licensee was focused significantly on the return to service of the Unit 1 TDAFW pump.
The licensee did not begin readily addressing the overall incident and circumstances surrounding the event until approximately June 21, 2007, when a root cause team was formed.
Following the machining of the original outboard bearing installed during the 10-year overhaul around June 14, 2007, the licensee implemented immediate corrective actions.
However, the inspectors walked down a quarantine area, and found parts missing for which the licensee could not account. The licensee subsequently established additional quarantine controls using a locked container with controlled keys, to ensure the preservation of components. The licensee wrote Condition Report CAP01096984 identifying the deficiencies in equipment quarantine procedures, practices and controls.
Analysis:
The inspectors determined the failure to establish adequate quarantine controls for the degraded Unit 1 TDAFW pump bearing was a performance deficiency that warranted a significance evaluation in accordance with IMC 0612, Power Reactor Inspection Reports, Appendix B, Issue Screening. This finding was more than minor because, if left uncorrected, the failure to properly quarantine items would become a more significant safety concern. Specifically, the failure to quarantine would impede the identification of causes for conditions adverse to quality, and therefore prevent the implementation of appropriate corrective actions.
The inspectors determined the finding impacted the human performance attribute of the Mitigating Systems Cornerstone. Using IMC 0609, Appendix A, Determining the Significance of Reactor Inspection Findings for At-Power Situations, Attachment 1, SDP Phase 1 Screening Worksheet for IE, MS, and B Cornerstones, the inspectors determined the finding was not a design qualification deficiency resulting in a loss of function per Generic Letter 91-18, did not represent an actual loss of safety function of a system or train of equipment, and was not potentially risk-significant due to a seismic, fire, flooding, or severe weather initiating event. Therefore, the finding was considered to be of very low safety significance (Green). The primary cause of this finding was related to a cross-cutting aspect in the area of human performance because the licensee did not ensure that procedures were adequate and accurate to assure nuclear safety (H.2(c)).
Enforcement:
10 CFR Part 50, Appendix B, Criterion V, requires, in part, that activities affecting quality be prescribed and accomplished by procedures appropriate to the circumstances. Contrary to the above, the licensee failed to ensure that appropriate procedures existed with prescribed actions to assure that failed safety-related equipment was quarantined and preserved, as necessary, to support causal analysis and ensure the appropriate corrective actions were developed to correct the condition, an activity affecting quality. Consequently, the licensee failed to adequately preserve the turbine outboard bearing for the Unit 1 TDAFW pump as the bearing was machined, removing the scuff and wear markings and any possible indications of potential heating of the bearing. Because this finding was of very low safety significance and because the finding was entered into the licensees corrective action program as CAP01096984, this violation is being treated as a non-cited violation (NCV) consistent with Section VI.A of the NRC Enforcement Policy (NCV 0500266/2007008-07; 0500301/2007008-07).
The licensee took immediate corrective actions to address the issue and has issued a new procedure, NP 1.1.17 Quarantine of Areas, Equipment, and Records.
4OA6 Meetings
Exit Meetings On July 12, 2007, the inspectors presented the preliminary inspection results to Mr. D. Koehl and members of his staff, who acknowledged the findings. The licensee acknowledged the information presented. The inspectors asked the licensee whether any materials examined during the inspection should be considered proprietary. No proprietary information was identified.
ATTACHMENTS: 1)
SUPPLEMENTAL INFORMATION
KEY POINTS OF CONTACT
Licensee Personnel
- R. Amundson, General Supervisor Operations Training
- C. Butcher, Site Engineering Director
- G. Corell, Radiation Protection and Chemistry Manager
- F. Flentje, Licensing Supervisor
- R. Harrsch, Operations Manager
- L. Hawki, Containment System Engineering Supervisor
- F. Hennessy, Program Engineering Supervisor
- C. Jilek, Maintenance Rule Coordinator
- T. Kendall, Engineering Senior Technical Advisor
- D. Koehl, Site Vice-President
- K. Locke, Regulatory Assurance
- J. McCarthy, Director of Site Operations
- G. Packard, Plant Manager
- L. Peterson, Design Engineer Manager
- M. Ray, Regulatory Affairs Manager
- J. Schleif, Assistant Operations Manager
- J. Schweitzer, Manager of Projects
- G. Sherwood, Engineering Programs Manager
- C. Sizemore, Training Manager
- B. Vandervelde, Maintenance Manager
- P. Wild, Design Engineering Projects Supervisor
Nuclear Regulatory Commission
- J. Cushing, Point Beach Project Manager, NRR
- J. Cameron, Chief, Reactor Projects, Branch 5
- S. West, Deputy Director, Division of Reactor Projects
- J. Caldwell, Regional Administrator
Attachment 1
LIST OF ITEMS OPENED, CLOSED, AND DISCUSSED
Opened
. 0500266/2007008-06 URI Inadequate Post-Maintenance Testing of the Turbine-
Driven Auxiliary Feedwater Pumps Following Major Maintenance (Section 4OA3.6.b.1)
Opened and Closed
0500266/2007008-01 NCV Failure to Identify and Correct Previous Indications of 0500301/2007008-01 High Bearing Temperatures (Section 4OA3.2.b.1)0500266/2007008-02 NCV Failure to Appropriately Assess the Operability of the Unit 1 Turbine-Driven Auxiliary Feedwater Pump on June 9, 2007 (Section 4OA3.2.b.2)0500266/2007008-03 NCV Failure to Have Procedures Appropriate to the 0500301/2007008-03 Circumstances for Turbine Overhauls (Section 4OA3.3.b.1)0500266/2007008-04 FIN Failure to Have Specific Formal Training for 0500301/2007008-04 Maintenance Craft on Turbine Overhauls (Section 4OA3.3.b.2)0500266/2007008-05 NCV Failure to Have Procedures Appropriate to the 0500301/2007008-05 Circumstances for the Analysis and Sampling of Safety-Related Turbine and Pump Oil (Section 4OA3.5.b.1)0500266/2007008-07 NCV Failure to Implement a Quarantining Process0500301/2007008-07 (Section 4OA3.7.b.1)
Discussed
None Attachment 1